Rod antenna for short waves



June 7,1938. 1W.VOIGT 2,119,692

ROD ANTENNA FOR SHORT WAVES.

Filed Oct. 25, 1935 TRANSMITTER INVENTOR. WILLI VOIGT BY I - I A ORNEY.

Patented June 7, 1938 i I ROD ANTENNA FOR SHORT WAVES Willi Voigt, Berlin, Germany, assignor to Telefunken Gesellschaft fiir Drahtlose, Telegraphic m. b. H., Berlin, Germany, a corporation of Germany Application October 23, 1935, Serial No. 46,381

In Germany September 26, 1934 V 1 Claim. (01. 250-33) In vertical antennas it is known, in order to roller 9 with adjustable mounting. The shaft of shorten the length of the antenna and to obtain roller 9 has a suitable handle mounted thereon a more favorable current distribution, to provide which, when turned, displaces the sliding conat the upper end of the antenna a self -inductance, tact 6.

capacity, or both. Such an arrangement is de- In shortening the length of the radiator by de- 5 scribed in German Patent No. 205,494. In the creasing the number of its individual parts, it will known construction the self-inductance is previof course be necessary to also shorten the length ously adjusted once and for all to the desired of the cord accordingly. To this end a suitable Wave range. The tuning is then controlled by winding up means In is provided which collects 10 means of a variable tuning element disposed near the superfluous length of the cord. In order to 10 the base of the antenna. tension the cord, the roller 9 will be moved down- In accordance with the present invention, this wards along a guide until the cord is sufficiently antenna arrangement can be improved by making tensioned, and following this the bearing of this the self-inductance carried by the antenna variroller is fixedly secured in place.

able for the P p Of tuning- The a a on of The electrical connection with the transmitter 15 the reactance of this self-inductance is suitably I2 is obtained by means of a lead l3. The anaccomplished bymeansof transmission andoperatenna is supported from an insulator I4 which tion of a suitable handle provided in the proximmay further be mounted to the transmitter casity of the base of the antenna. The antenna ing. The insulator may also be provided with proper is preferably formed of rods or tubes the attachment ll serving for fastening the 2 placed on top of each other, whereby the length roller 9. of the antenna may be varied by adding or remov- What is claimed is: ing single parts thereof. With this arrangement An antenna comprising a vertical aerial comit is possible to vary the range of the antenna posed of a plurality of serially arranged collapsradiation approximately proportional to the ible rods, an inductance coil connected to the top 25 length of the antenna. portion of the uppermost rod of said aerial, a

An embodiment in accordance with the invencapacity surface connected to the top of said tion is shown in the accompanying drawing, coil, a metallic arm connected to one end of and given by way of example, wherein the actual arranged parallel to the length of said inductance linear radiator is composed of rods or tubes l, 2 coil, and means for tuning said antenna comprisso and 3. A self-inductance 4 is fixedly secured to ing a guide roller mounted near the top of said the upper end of the antenna, and to it a capacivertical aerial, a drive roller mounted near the tive surface 5. For the control of the inductance base of said vertical aerial, and a cable passing there is provided a contact 6. This contact is over both said rollers, said cable having attached suitably controlled in such manner that it is thereto a sliding contact arrangement engaging fixedly secured to a control cord 1 and moved both said coil and said arm for varying the selftherewith. The cord is guided at the top of the inductance of said coil. antenna across a guide roller 8 fixedly mounted WILLI VOIGT. thereat, and at the bottom it is passed over a drive 

